le tourneau



Feb. 9, 1960 R. G. LE TOURNEAU 2,924,077

MOBILE SEA PLATFORM 4 Sheets-Sheet 1- Filed Dec. 3, 1956 INVENTOR.flak/z & LaTozzmsam BY Feb. 9, 1960 R. G. LE TOURNEAU 2,924,07?

MOBILE SEA PLATFORM 4 Sheets-Sheet 2 Filed Dec. 3, 1956 M mm mm M fw WV7% Z r mm W y 1960 R. G. LE TOURNEAU 2,924,077

MOBILE SEA PLATFORM 4 Sheets-Sheet 4 Filed Dec. 5, 1956 INVENTOR./?006ff G. Lefiwweaa BY United States Patent MOBILE SEA PLATFORM RobertG. LeTourneau, Longview, Tex.

Application December 3, 1956, Serial No. 625,710

3 Claims. (Cl. 61-46.5)

My invention relates generally to improvements in mobile sea platforms,and particularly to a floatable vessels which are convertible intostabilized structures over bodies of water. My invention is especiallyapplicable to offshore or tidelands oil exploration, drilling, andproducing operations.

This application includes disclosure of certain improvements over theMobile Sea Platform of my copending application Ser. No. 473,885, whichwas filed on December 8, 1954. In the co-pending application there isdisclosed mobile seat platforms wherein the fiotatable hull structureincorporates cylindrical members as principal hull elements, and whereinspud well structures are fixed to the outboard side of such hullmembers. The co-pending application further discloses spud towers, eachmade up of a plurality of tubular spud columns held in fixed parallelspaced relation by latticed truss- Work members, with a rack carried byeach spud column. Additionally the co-pending application discloses theuse of a plurality of electric motor driven gear units per rack, thegear units being mounted to the spud well and each having an outputpinion in driving engagement with an associated rack.

The construction of a mobile sea platform incorporating the principlesand elements outlined immediately foregoing presents a number ofsignificant problems.

Among these problems is that of how to mount a plurality of rack driveunits in rack engaging relation while fulfilling requirements forstructural rigidity, rack and pinion alignment, space economy,maintenance accessibility, and simplicity and practicality of assembly.Another problem is that of providing a spud well structure capable ofwithstanding and transmitting the tremendous forces from the rackengaging pinions to the hull body, having in mind that as little asabout 1% of lateral deformation in the spud well diameter would nearlydisengage, and possibly jam, a pinion. A further problem is that ofeffectively mounting a rack on a basically tubular column withoutresorting to special and elaborate build-up between the rack and thecolumn.

It is accordingly the broad object of my invention to provide animproved mobile sea platform of the general type disclosed in myco-pending application.

Another object of my invention is to provide effective solutions for thespecific problems aforementioned.

These and other objects are effected by my invention as will be apparentfrom the following description taken in accordance with the accompanyingdrawings, forming a part of this application, in which:

Fig. 1 is a schematic plan view of the improved mobile sea platform ofmy invention, with the spud towers removed;

Fig. 2 is a schematic front elevational view of the platform with therear spud tower removed;

Fig. 3 is a schematic section view taken along lines 3-3 of Fig. 1;

Fig. 4 is an enlarged schematic plan view of a spud ice well and spudtower, with the spud tower pontoon omitted, and with the spud well topcovering removed;

Fig. 5 is a schematic front elevational view of a rack drive assembly;

Fig. 6 is an enlarged schematic plan view of a rack drive assemblyengaging the rack of a spud column;

Fig. 7 is a schematic section view taken along lines 7-7 of Fig. 4, withdriving units removed;

Fig. 8 is a schematic section view taken along lines 88 of Fig. 4;

Fig. 9 is a detailed view of decking structure; and

Fig. 10 is an enlarged schematic perspective view showing a segment of aspud tower column and rack.

Turning now to the drawings, the basic structure of the platform isshown by Figs. 1, 2, and 3. The hull comprises a pair of spaced parallellongitudinally extending cylindrical members 11, 13 closed at theirforward ends. A transversely extending cylindrical member 15 is disposedbetween the longitudinally extending members at their rear end portions.The rear ends of the longitudinally extending members 11, 13 and theends of the transversely extending member 15 are shaped to match, andcorresponding ends are welded together to form a generally U-shapedwater-tight unitary structure. The longitudinally extending hull membersare held in rigid spaced relation by'a plurality of top and bottom crossbeams 17, 19 (Fig. 3)'located at intervals along the length of thelongitudinally extending cylindrical members. Additional rigidity forthe structure is obtained by use of a plurality of vertical corrugatedbulkheads 21 each extending between the parallel spaced cylindricalmembers transversely thereof, and at spaced intervals along the lengthof said members. The hull bottom 23 is made up of longitudinallyextending corrugations formed by welding steel plates and joined to thebottom portions of the cylindrical members to form a watertightstructure. The hull front end wall is disposed between the parallelspaced cylindrical members some distance from the front ends of saidmembers as indicated at 21 in Fig. 1. The hull deck is slotted at itsfront end portion, with the slotted portion 25, being adapted forreceiving a derrick (not shown). The deck at the sides of the slot issupported by suitable bracing memr bers 27. The vessel hull carriesthree spud wells 29, 31,

33. The two forward spud wells 29, 31 are aligned transversely of thehull structure near its forward end, each being fixed to the outboardside of a respective longitudinally extending cylindrical hull member11, 13. The rear spud well 33 is centered on the rear cylindrical member15 and fixed to the outboard side of same. Each spud well is made up ofpieces of heavy steel plates formed and welded together to make aunitary structure. The inner wall 35 of the spud well is cylindrical inshape. The spud well outer wall 37 is parallel to and spaced outwardlyfrom the inner wall to the diameter of the inner wall which is parallelto the longitudinal axis of the cylindrical hull member to which it isfixed and then extending to said member in a plane perpendicular to saidaxis. The spud well has a top 39 and a bottom 41 made of steel platematerial bridging between the inner and outer walls, and has also twointermediate walls 45, 47 parallel to the top and bottom and dividingthe well structure into three horizontal compartments, as shown by Fig.8. The marginal edges of the ends of the spud well outer wall are shapedto conform to the contour of the cylindrical hull member and are weldedthereto. A portion 49 of the outboard side of the cylindrical hullmember, conforming to the shape of the spud well inner wall, is cutaway, so that said inner wall 35 fits into the cut away portion and isWelded thereto.

Each spud well carries three rack drive assemblies,

3 51, S3, 55 details of which are shown by Figs. 5, 6, and 7. Each rackdrive assembly comprises a gear case 57 which mounts a plurality of.drive units 59. The gear case is a. rigid. unitary structure comprisinga pair of spaced parallel. side walls 61, 63 made. of heavy steel platematerial, and an end wall 62:. One side wall carries three large boltrings 65, while the other side wall carries four large bolt rings 65.When the gear case side wallsare assembled, the bolt rings arestaggered. so that the, central axis of, any bolt ring 65 is spacedequally from the central axes of adjacent bolt rings. The gear case sidewalls are held in rigid spaced relation by partition members 67. Eachpartition member is a substantially rectangular steel plate the marginaledges on three sides of which abut and are welded togear case side walls61, 63 and end wall 62. The fourth side of each partition member isslotted as shown at 43 in Fig. 6 to expose the drive unit rack engagingpinlons 81 so that they may receive the rack 91. Alternate partitionmembers 67 are mutually parallel, while adjacent partition members formthe sides of frustro-isosceles triangles, the base of which spans aboltring, 65 with the base perpendicular bisector coinciding with thebolt ringcentral axis. Reinforcing bars 69, 71, 73 are welded to eachpartition member, one adjacent each side of the slot 43 and one adjacentthe bottom of the slot. The lines of intersection of thepartitionmembers with the gear case side walls are mutually parallel andare perpendicular to the longitudinal axis of the side walls.

There are three gear case assemblies 51, 53, 55 disposed in each spudwell 29, 31, 33. Each gear case 57 is incorporated into the spud Wellstructure in uprightposition between the spud well inner 35 and outer 37walls, with the gear case side walls 61, 63 being welded to the spudwell inner wall 35, the spud well top and bottom 39, 41, and the spudwell intermediate partitions 45, 47. The gear. cases 57 are spaced 120degrees apart, and so that a respective vertical plane passing throughthe spud well center is parallel to and equally spaced from the sidewalls of a respective gear case with the slots 43 in gear case partitionmembers facing the spud well center, and one of said planes beingperpendicular to the longitudinal axis of a cylindrical hull member 11,13 to which the spud well is fixed.

Each drive unit comprises an electric motor 75 fixed in driving relationto a primary gear box which is in turn fixed to an output gear box 79.Each electric motor 75 is equipped with an electromagnetic brake 83,which is automatically engaged when the motor is de-energized. Eachoutput gear box 79 is generally dish-shaped and carries a bolt flange 86at its large peripheral portion, which bolt flanges is matched to thecorresponding gear case bolt ring 65. Thus each drive unit 59 is anintegral assembly which is bolted to a respective gear case bolt ring65. Each output gearbox 79 carries a rack drive pinion 81 which isdisposed on the output gear box central axis at the gear box small endportion.

Each spud well 29, 31, 33 is of course designed to receive a spud tower85. The spud towers are of triangular transverse cross section and eachcomprises three spud columns 89 at the triangle vertices and held inrigid spaced parallel relation by tubular latticed truss-work members95, 97,98. At spaced intervals along the spud column length there is atubular truss member 95 disposed between each pair of adjacent spudcolumns 89 and lying in a horizontal plane. Additional sets of trussmembers extend at various spud tower levels from adjacent spud columnsboth upwardly and downwardly to converge at the midpoints of respectivehorizontal trussmembers 95. Additional truss-members 97, 98 extend fromthe spud columns 89 and from the midpoints of the horizontal trussmembers 95 to converge at the intersection of perpendicular bisectors ofthe spud tower triangle to support a jetting conduit 99. Each spud towercarries a water-tight cylindrical pontoon tank 87' at its 4 a lower end.Each pontoon tank is provided with a sea cock (not shown) for floodingand draining purposes. The jetting conduit 99 extends down through thepontoon tank and is for the conventional well known purpose.

Each spud column 89 is a basically tubular member having a generallytear drop transverse cross section as shown by Fig. 10 with a slitformed along the length of the column at the small end of the tear drop.The tear drop tubular member is formed by bending a strip of heavy steelplate material to the tear-drop shape. A gear rack 91 is received in theslit and aligned to be centrally disposed ina plane passing through thelongitudinal' axis of the column. The rack 91 is welded on each side asat 93 to the respective column 89. The spud towers are so dimensionedthat the racks 91 properly engage respective sets of drive unit outputpinions 81. Suitable guides (not shown) are provided to preventexcessive sideways displacement of the racks 91 with respect to thedrive pinions 81.

The spud well intermediate partition walls 45, 47 are cut back in theareas adjacent the gear cases 57 to provide access wells 101 asindicated by Figs. 4 and 7. On the sides of the two gear cases adjacentthe hull, the hull cylindrical member is cut away to provide accesswells. A vertical spud wellsupport plate 105 extends from the hullcylindrical member and perpendicular to its longitudinal axis to thespud well inner wall 35, and serves also as one wall of the access wellin the case of. the gear cases adjacent the hull. A hinged cover plate103 is provided for each gear case access well 101 just above the hulldeck level.

Thehull decking, or floors, are made up of beams 111 formed from stripsof the'steel plate material. The transverse cross section of adecking-beam is shown by Fig. 9, and includes a surface portion 113,adownwardly extending'short flange 115 onone side of the surfaceportion, and a generally block J shaped flange 117 depending from theother side of the surface portion 113. The decking beams are joined attheir longitudinal edges by welding, with the outer surface of the shortflange 115 of one beam bearing against the outer surface of the upperportion J shaped flange 1170f the adjacent decking beam, with thesurface portions 113 of the decking beams lying generally in a commonplane.

The manner of operation, and the electrical system of the mobile seaplatform herein described is essentially the same as that of theplatform disclosed by my copending application aforementioned. It willbe apparent from the foregoing that I have provided effective soluetions for a number of serious problems in mobile sea platform design andconstruction. The concept of building the large gear cases as integralunits and then incorporating them into the spud well structure, with aplurality of individual power units removably fixed to each gear case,is an effective solution to one serious problem. Thespud tower columnstructure disclosed herein results in a basically tubular column and yetprovides surfaces for receiving the racks so that welding is convenientand no special build-up? is required. The spud well structure disclosedherein is remarkably simple and yet has amazing structural quality.

While I have shown my invention-in only one form, it will be obvious tothose skilled in the art that it is not so limited, but is. susceptibleof various changes and modifications without departing from the spiritthereof.

I claim:

1. In a vessel convertible into a stabilized structure over a body ofwater and 'of a type wherein the vessel may be raised or lowered on spudtowers having racks engaged by pinions driven by electric motors, adriving assembly for each rack comprising a unitary gear case fixedrigidly to the vessel and having parallel spaced side walls, a pluralityof bolt rings integral with one side wall and each surrounding aseparate opening in said wall, a pluralityof boltrings integral withthe..other side wall and surrounding openings therein which arestaggered with respect to the openings in the opposite side wall, eachsaid bolt ring adapted to receive a drive unit comprising an electricmotor driven gear box having an output pinion with the output pinions ofall of said drive units being aligned, and an opening inone face of saidgear case for receiving a rack, with all of said pinions engaging saidrack.

2. In a vessel convertible into a stabilized structure over a body ofwater and of a type having a hull comprising a cylindrical main member,with a spud well carried by said member, with a spud tower in said welland having rack mounting tower columns with the rack in each caseengaging pinions of drive units carried in said well; a spud wellstructure comprising a circular inner wall, an outer wall spacedoutwardly from said inner wall, said outer wall having a first portionwhich is parallel to the outermost half of said inner wall and secondand third portions which extend from the respective ends of said firstportion to said member in respective planes which are perpendicular tothe central axis of said member a top and bottom bridging between saidwalls, intermediate walls parallel to said top and bottom walls anddividing said well into horizontal compartments, a unitary gear caseadjacent each rack mounting tower column and having side walls adaptedfor receiving a plurality of drive units, said gear case side wallsbeing fixed to said inner spud well wall and parallel to a verticalplane passing through a diameter of said inner wall and midway betweensaid gear case side walls.

3. In a vessel convertible into a stabilized structure over a body ofwater and of a type wherein the vessel may be raised or lowered on spudtowers having racks engaged by pinions driven by electric motors, adriving assembly for each rack comprising a unitary gear caseincorporated into the vessel structure, said gear case having a pair ofspaced side walls and an open side, each side wall having a plurality ofspaced openings therein each surrounded by a bolt ring, a plurality ofdrive units each comprising an electric motor driven gear box having anoutput pinion, one of said drive units being removably received by eachsaid bolt ring with all of said output pinions extending within saidgear case and vertically aligned, each of the racks extending into acorresponding one of said gear cases thru the open side thereof, withall of said pinions engaging said rack.

References Cited in the file of this patent UNITED STATES PATENTS 85,598Lewis Jan. 5, 1869 1,732,438 Gardner Oct. 22, 1929 2,049,605 DriemeyerAug. 4, 1936 2,260,009 Doran et a1. Oct. 21, 1941 2,271,344 Rauch Jan.27, 1942 2,308,743 Bulkley et al Jan. 19, 1943 2,775,869 Pointer Jan. 1,1957

